关系数据库表之间的关系:
1 正确 1
1 正确 许多
许多 正确 许多
表间关系设计
基于主键关联
基于外键关联
基于中间表
1 对 1关系实现:
基于主键关联
基于外键关联
基于中间表
1 对 多关系实现:
基于外键关联
基于中间表
多 对 多关系实现:
基于中间表
面向对象实体关系
1 对 1
1 对 多
多 对 多
方向 :
单向、双向
CRUD:
many2one配置:
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.demo.model"> <class name="Certificate" table="t_certificate"> <id name="certificateId" column="certificate_id"> <generator class="sequence"><param name="sequence">SEQ_T_CERTIFICATE</param></generator> </id> <property name="certificateName" column="certificate_name"/> <property name="certificateNo" column="certificate_no"/> <many-to-one name="student" column="student_id"></many-to-one> </class> </hibernate-mapping><many-to-one name="student" column="student_id"></many-to-one>增、删、改
@Test public void addTest() { Student student = new Student(); student.setStudentName("王五"); student.setAge(35); Certificate certificate1 = new Certificate(); certificate1.setCertificateName("aa"); certificate1.setCertificateNo("3a10001"); certificate1.setStudent(student); Certificate certificate2 = new Certificate(); certificate2.setCertificateName("bb"); certificate2.setCertificateNo("3a10002"); certificate2.setStudent(student); Session session = null; try { session = HibernateUtil.openSession(); session.beginTransaction(); // 先保存one,再保存many session.save(student); session.save(certificate1); session.save(certificate2); session.getTransaction().commit(); } catch (Exception e) { session.getTransaction().rollback(); e.printStackTrace(); } finally { HibernateUtil.closeSession(session); } } @Test public void deleteTest() { Student student = new Student(); student.setStudentId(1); Certificate certificate1 = new Certificate(); certificate1.setCertificateId(1); Certificate certificate2 = new Certificate(); certificate2.setCertificateId(2); Session session = null; try { session = HibernateUtil.openSession(); session.beginTransaction(); session.delete(certificate1); session.delete(certificate2); session.delete(student); session.getTransaction().commit(); } catch (Exception e) { session.getTransaction().rollback(); e.printStackTrace(); } finally { HibernateUtil.closeSession(session); } } @Test public void updateTest() { Student student = new Student(); student.setStudentId(2); student.setStudentName("赵四"); Certificate certificate1 = new Certificate(); certificate1.setCertificateId(3); certificate1.setCertificateName("cc"); certificate1.setCertificateNo("s0001"); certificate1.setStudent(student); Certificate certificate2 = new Certificate(); certificate2.setCertificateId(4); certificate2.setCertificateName("dd"); certificate2.setCertificateNo("s0002"); certificate2.setStudent(student); Session session = null; try { session = HibernateUtil.openSession(); session.beginTransaction(); session.update(certificate1); session.update(certificate2); session.update(student); session.getTransaction().commit(); } catch (Exception e) { session.getTransaction().rollback(); e.printStackTrace(); } finally { HibernateUtil.closeSession(session); } }getTest:
@Test public void updateTest() { Student student = new Student(); student.setStudentId(2); student.setStudentName("赵四"); Certificate certificate1 = new Certificate(); certificate1.setCertificateId(3); certificate1.setCertificateName("cc"); certificate1.setCertificateNo("s0001"); certificate1.setStudent(student); Certificate certificate2 = new Certificate(); certificate2.setCertificateId(4); certificate2.setCertificateName("dd"); certificate2.setCertificateNo("s0002"); certificate2.setStudent(student); Session session = null; try { session = HibernateUtil.openSession(); session.beginTransaction(); session.update(certificate1); session.update(certificate2); session.update(student); session.getTransaction().commit(); } catch (Exception e) { session.getTransaction().rollback(); e.printStackTrace(); } finally { HibernateUtil.closeSession(session); } }结果:
Hibernate: select certificat0_.certificate_id as certific1_1_0_, certificat0_.certificate_name as certific2_1_0_, certificat0_.certificate_no as certific3_1_0_, certificat0_.student_id as student4_1_0_ from t_certificate certificat0_ where certificat0_.certificate_id=? 3 证书名称:cc Hibernate: select student0_.student_id as student1_0_0_, student0_.student_name as student2_0_0_, student0_.age as age0_0_ from t_student student0_ where student0_.student_id=? 学员名称:赵四Student(one)对象被延迟载入了,many2one中,get支持延迟载入
loadTest:
@Test public void loadTest() { Session session = null; try { session = HibernateUtil.openSession(); session.beginTransaction(); Certificate certificate = (Certificate) session.load( Certificate.class, 3); System.out.println(certificate.getCertificateId()); System.out.println("证书名称:"+certificate.getCertificateName()); System.out.println("学员名称:"+certificate.getStudent().getStudentName()); session.getTransaction().commit(); } catch (Exception e) { session.getTransaction().rollback(); e.printStackTrace(); } finally { HibernateUtil.closeSession(session); } }
结果:
3 Hibernate: select certificat0_.certificate_id as certific1_1_0_, certificat0_.certificate_name as certific2_1_0_, certificat0_.certificate_no as certific3_1_0_, certificat0_.student_id as student4_1_0_ from t_certificate certificat0_ where certificat0_.certificate_id=? 证书名称:cc Hibernate: select student0_.student_id as student1_0_0_, student0_.student_name as student2_0_0_, student0_.age as age0_0_ from t_student student0_ where student0_.student_id=? 学员名称:赵四
many与one都被延迟载入
补充表结构及实体类源代码:
t_student
t_certificate:
Student:
package com.demo.model; import java.io.UnsupportedEncodingException; /**学生信息双向 * @author wobendiankun *2014-10-19 下午08:54:29 */ public class Student { private int studentId ; private String studentName ; private int age; public int getStudentId() { return studentId; } public void setStudentId(int studentId) { this.studentId = studentId; } public String getStudentName() { return studentName; } public void setStudentName(String studentName) { this.studentName = studentName; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { String str=""; if(studentName!=null){ try { str=new String(studentName.getBytes("UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } return "Student [studentId=" + studentId + ", studentName=" + str + ", age=" + age + "]"; } }
Certificate
package com.demo.model; /**从业资格证书 * @author wobendiankun *2014-10-25 上午11:43:21 */ public class Certificate { /** * 证书id */ private int certificateId ; /** * 证书名称 */ private String certificateName; /** *证书编号 */ private String certificateNo ; private Student student ; public int getCertificateId() { return certificateId; } public void setCertificateId(int certificateId) { this.certificateId = certificateId; } public String getCertificateName() { return certificateName; } public void setCertificateName(String certificateName) { this.certificateName = certificateName; } public String getCertificateNo() { return certificateNo; } public void setCertificateNo(String certificateNo) { this.certificateNo = certificateNo; } public Student getStudent() { return student; } public void setStudent(Student student) { this.student = student; } }
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时间: 2024-10-12 21:55:06